Camera Orientation

[Beardy Bob]

Probably a very silly question with a very simple answer, BUT...

How do you ensure that the camera is in the same orientation relative to your chosen target (e.g. M31) each night?

[Merlin66]

If orientation is an issue over a period of time I use a bit of masking tape on the camera and on the focuser then mark a registration line.

That way you can put the camera back in place, well pretty close each time. This will work with an Equatorial mount... on an Al-Az the position angle ( as recorded on the CCD) varies with the time of night......

( I sometimes need to do this with the spectroscope to make sure the spectrum clears background stars)

[roundycat]

as above or use a tri square on camera body and align by sight with something on the mount or spirit level and point scope south then align camera with horizontal.

Dennis

[Merlin66]

Roundycat,

That would work if you only wanted the camera sitting square to the RA direction. Not sure that was the question asked??

[jgs001]

I like the idea of the tape... gonna have to start using that...

[roundycat]

It wasn't the question asked but it is the way I do it as I cannot abide showing astro pictures that are not presented much as terrestrial pictures are expected to be, ie, upright.

Dennis

[blinky]

I dont bother too much TBH when stacking in something with DSS they dont all have to be the same way round it will sort them during the stacking process.

[Ibbo!]

Tipex is good

Steve

[tooth_dr]

That is ok if the object is small in the field, if the object extends throughout the frame, getting it close is pretty important!

I like the idea of tape, I must remember that one for the future. Good tip Merlin66

[George]

Im on the same chair as Roundycat, my DSLR is orientated north/south whenever possible, the odd time its rotated to fit a very large target. My DSLR is left connected to the scope all the time otherwise new flats would be needed every imaging session.

Ive used tape trick myself on many occations.

[Psychobilly]

Most of the time mines set either 90 or 0 degrees to RA but when i need to rotate it I have made up some angle scales which I have "taped" to the rotating parts , or I use a Wixey...

Peter...

[Beardy Bob]

Good tips, thanks. But I think you're assuming I have far knowledge than I deserve! What I'm trying to figure is far more fundamental and probably something that you'd simply assume everyone knows already. But here goes...

If I never remove or rotate the camera from an equatorial mount between sessions, will any given target always be in the same orientation in the camera (given that the position of the target in the sky changes over the year)?

Answers along the lines of, 'of course it will you numpty, it's an equatorial mount' welcomed! But I want to be sure before I try taking data and, for many irrelevant and tiresome reasons, my brain is only working at about 5% capacity at the moment and I just can't picture it mentally.

[jgs001]

Bob, I think you're right... that's my understanding anyway, although I may well be wrong...

[George]

Only targets that would be visible year long are circumpolar. Any other target travels along an imaginary line, the orientation wont change if you use an equatorial mount as the mount follows the same imaginary line as the target. Alt Az mounts would rotate the target AFAIK.

[roundycat]

Yes

Dennis

[Merlin66]

Answers along the lines of, 'of course it will you numpty, it's an equatorial mount' welcomed! -Yes.

For all "fixed" objects in the sky ie stars, galaxies, DSO's etc

Comets and planets etc because of their movement will have different orientations.

[Beardy Bob]

As I thought. Thanks for the confirmation guys. Now I just need some clear nights to actually get some data. I've been waiting for over two weeks now and haven't seen a single star through all the cloud!